1. Field of the Invention
The invention relates generally to multiple piece buckles having at least one male member and one female member which are disengaged by depressing a resilient flap or the like on one of the members.
2. Description of Related Art
Assorted two-piece buckles are known in the art. These buckles typically include a female receptacle or socket member which is engageable with a male latch or plug member. One or both of the members adjustably or fixedly holds a strap or belt around crossbars or the like. One particularly common form of a two-piece buckle is a so-called side-release buckle in which the plug member includes a pair of legs which, when inserted into the socket member, flex inwardly and slide past opposing stop members (e.g., latches) in the socket until they snap fit into respective side openings in the socket. The stop members are typically inwardly projecting surfaces of the socket member around the periphery of the opening which engage with shoulders defined on the outside edges of the legs of the male member. The two buckle pieces are unlocked and disengaged by squeezing the legs of the male member through the openings in the female member between the thumb and forefinger, thereby freeing the shoulders defined in the legs from the respective stop members in the female member and allowing the two buckle pieces to become separated.
An example of such a side-release type buckle is disclosed in U.S. Pat. No. 4,150,464. It can be seen that the female member defines apertures in opposing side walls thereof for engagement with shoulders of the latch arms belonging to the male member. The shoulders are positioned on the outside side surfaces of the latch arms and engage the stop members which project inwardly from the side walls of the female member. However, it has been recognized that with this arrangement, the buckle is susceptible to failure during heavy loading for the following reasons. The load in the latch arms which urges removal of the latch arms from the female member is ordinarily directed along the longitudinal axis or center line of each latch arm. However, the line which represents the location of the latch resistance or engagement force opposing the load is offset from center line, because it is directed between the side walls of the female member and the shoulders on the outer side surfaces of the latch arms. Accordingly, it has been recognized that during loading on the buckle, a torque develops between the latch arms and the female member which tends to cause inward rotation of the latch arms, and consequently release of the buckle (see also U.S. Pat. No. 5,222,279 (col. 1, 1. 43-48). U.S. Pat. No. 5,222,279 proposes a solution to this problem for a side-release type buckle.
Notwithstanding the above-described drawback, side release buckles have found wide use in luggage, baggage, sporting equipment, etc. . . . However, they have not found universal acceptance because in certain applications it is desirable to be able to release the buckle pieces in a different manner (i.e., without squeezing the buckle between opposite sides with two fingers). For example, in certain applications where someone wearing mittens may find it difficult to open a side release buckle, it is desirable to have a buckle which can be released with less dexterity.
Accordingly, two-piece buckles have been developed which are releasable by depressing a button or the like on a top face of one of the buckle members. Examples of these types of buckles are described in U.S. Pat. Nos. 4,802,262; 4,864,700; 4,866,819; and 4,894,890 to Kasai. The plug member of these buckles includes a locking lug near the distal end thereof which, when inserted into the socket member, slides over a stopper crossbar in the socket. Once it is beyond the stopper bar, the locking lug snaps into place behind it thereby preventing the plug member from being removed. The two pieces of the buckle are disengaged by depressing a resilient flap located in the center region of a top or bottom face of the socket member. The inside surface of the flap has a releasing lug which acts on the locking lug of the plug member to push it away from the stopper bar, thereby freeing the plug member from the socket member. Thus, these types of buckles merely require one finger to push down on the flap or button to disengage the two pieces.
However, one drawback to these push button-type buckles is that they generally have a complex structure as compared to side release buckles. Another drawback is that they often do not exhibit the same level of strength or holding power as side-release buckles. The latch or shoulder resistance force which opposes the load force on a side-release buckle, as described above, is typically greater than the locking lug force which opposes the load on a push button type buckle.
Accordingly, it would be desirable to combine the great latch resistance or shoulder resistance force of a side-release buckle with the single push button or flap releasing mechanism of a push button type buckle. It would also be desirable to provide a push button type buckle wherein the engagement force between the male and female members, which holds the two buckle pieces together against the load force, is aligned in all directions with the load force, in order to further improve the locking strength of the buckle.